Aerodynamic brake



Oef. 14, '1947. w, H, HUNTER 2,428,936

AERODYNAMIC BRAKE Filed Sept. l0, 1945 lllllllllllvllllllll- V I Patented Oct. 1.4, 1947 B. F. Goodrich Company,

eoriioratien of New York Application september 1o, 1.943, serai No. 501,184

8 Claims.

Thiseiriveiitiori relates to aerodynamic. breites grid other Sooilersfor aireretit and ie useful espeeiallv for'@replication to wine etriietiiree and other eirioils aiidstruetiires. of aircraft Wlier.l the airioil oi other structure is provided with an inflateble vprotective Covering ,for preventing the eCoiimul-etiori of ice at the leading edge thereof,A the, invention may be applied in association with arid in continuation ci such protective Covering for cooperation therewith and. for maintaining the desired Yaeifodvnamio. characteristics of the structure. and for. preventing the accumulation oi ice. thereon.

Principal objects of the invention are to provide an eflective aerodynamic spoiler for aircraft; to provide effectively for moving an elementto and from a dragrincreasing position by fluid operation; to provide for elastically holding the, element in a retracted position relative to the aircraft while permitting Athe advance of the element to 'the braking position; to provide. for protection of the spoiler'structure and mechanism; to provide for .maintaining a substantially smooth aerodynamic rflow/.of air acrossr the spoiler in its re. tracted'condition;and-to provide simplicity of construction, :and convenience of manufacture and servicing. f- More specicobjects'are to provide an aero.- dynamic brake operable by inflatable means, to provide a brakingstru'cture in continuation of and cooperable with an inflatable protective cov-` ering .for preventing ice accumulation onan airfoil, and to provide a braking structure generally triangular in section for presenting an edge to the now of air when in the braking position.

.These and other objects and advantages of the invention will be apparent from the following description.

4In the accompanying draWi-ngs, which form a part of this specification', and'in which like nunierals. areV employed to designate likeV parts throughout the same, V

Y Fig. l is a perspective view of aerodynamic brakes. mounted on an aircraft the` wings of the latter having associated inflatable protective coveri'ngs,V and con-structed in accordance with and embodying .the invention, parts being ,broken away. I i i' Fig. 2 is a sectional view taken along line 2-2 of Fig. '1,' parts being` broken away,

Y Fig- 3 iS a. viewliifre- Fie- .2 bili Showing the brakeY ifi-thebidkliis position, ioetrtsbeine broken away,

4 .is perspective view' cfa hinged flap element of the brake, parts beingbrokenaway,y

locations inay be utilized, if desired. The aircraftl I3 alsobe provided with inatable protective coverings IG disposed at the leading edges of 'the wings for preventing` the accumulation of ice thereon, The protective covering, or shoe, I6 preferably is elastic and adapted to be mounted in a condition of stretch upon the wing I 2 or airfoil and includes ak sheet vI'I of elastic material, such, f or example, as resilient rubber or other rubber-like material, and an inilatable tube or tubes I at the leading edge of the Wing I2, and

which'may be made of extensible or substantially non-extensible woven fabric impregnated or coated with a suitable rubber-like material. The shoe is 2in elQIlgate structure preferably tapering in width in accordance with the tapering thickness of the air foil..

At the upper and lower margins I9 and 20 of the shoe I6, attaching means are provided for mounting the shoe on the airfoil, which margins may be attached in substantially the same manner except that the lower margin 20 is not provided with a fairing strip 2|, but is constructed as shown especially in Fig. 5, in order to permit the continuation of the brake structure with the shoe. A fabric strip 22 is provided along the margins I9 and 20 of the shoe and united to the rub-ber thereof, the strip being folded to accommodate a metallic strip element 23, which may be of nat wire, extending throughout the margins of the shoe.

For attaching the shoe I6 to the wing I2, screws 25 are disposed through the shoe just inside the wire 23, the screws being mounted in hollow threaded rivets 26 set into the metal surface of the wing, and the arrangement being such that the wire 23 behind the screws 25 is adapted to maintain the shoe in a condition of tension between the upper and lower margins I9 and 20. The fairing strip 2| may be provided over the upper margin I9 of the shoe at the wire 23 yto providean even surface for the air flow and this strip may also be held in place by the screws 25.

Thev construction shown especially in Fig. 5 provides for attaching the lower margin of the protective covering I6 and provides for arranging the aerodynamic brake I in continuation therewith and additionally facilitates mounting the brake to the lower metal surface of the wing |2. Such an arrangement also provides surface continuity and facilitates maintaining the aerodynamic characteristics of the surface.

The brake lll includes a substantially flat nap element. 21 of stiff material such, f or example, as steel or aluminum sheet, which element is desirably hinged in the manner shown especially in Figs. 3, 4 and 5. The ap element 21 has a portion 28 extending from a hinge 29, which portion 2S may be secured at the lower margin 20 of the-shoe i3 by screws 25 extending through apertures 4| in the portion 28. The flap element 21 is disposed such that the hinge 29 overlies the I2, while the portion 28 is surface of the wing disposed in a recess 39 extending along the lower margin 23 of the protective covering I6.

The brake lil also includes an elastic covering 3| of suitable rubber-like material overlying the flap element 21 and preferably held in a condition of tension between front and rear margins, which maintains the flap 21 in a depressed position as shown especially in Fig. 2. The elastic covering 3| may be attached at its front margin 32 to the protective covering I6 and to the portion 23 of the nap 21 by a suitable adhesive material, such, for example, as rubber cement, the elastic covering 3| being of such thickness as to be disposed within the recess 33 whereby a flush outer surface at the region of juncture of the margins 23 and 32 is provided.

The rear margin 33 of the elastic covering 3| is desirably divided for providing an inner portion 35 and an outer extension 35, and a metal fairing strip 3S is disposedbetween the inner portion 34 and the extension 35 and also is disposed between the outer extension 35 and the wing l2, as shown especially in Figs. 2 and 3. The rear margin 33 may be attached to the wing l2 by means of screws like screws 23 extending through the fairing strip 3S and the portion 39 and engaging hollow threaded rivets 26. The inner portion 33 and the outer extension 35 of the elastic covering 3| may be adhered to the fairing strip 33 by a suitabie adhesive. This construction provides for tapering the brake I9 to a thin edge at the region of the rear margin 33 for facilitating smooth now of air while providing for placing the elastic covering 3| in a condition of tension.

The brake ifi includes an inflatable tube 31 of elongate form which may be extensible or substantially non-extensible in its walls, and which may be of suitable woven fabric impregnated or coated with suitable rubber-like material, or may be made wholly of rubber-like material. rEhe inatable tube 31 is disposed between the flap element 21 and the wing |2, and may be positioned directly against the flap element 21. A filler element 33 of suitable material such, for example, as sponge rubber, may be adhered by suitable adhesive to the elastic covering 3| and disposed between the inflatable tube 31 and the divided rear margin 33 and between the elastic covering 3| and the wing |2 for maintaining the outer surface of the brake |9 even from the inflatable tube to the region of the rear margin 33.

The margins of the elastic covering 3| are attached in the manner described hereinabove for maintaining the covering 3| in a state of tension, and in the preferred construction the covering 3| is not adhered to the iiap element 21 except at the portion 28 thereof so that the covering can stretch and have movement relative to the flap during iniiation of the tube 31.

As shown especially in Fig. 6, the elastic covering 3| may be provided with a reinforcing strip 39 of woven fabric or other suitable material disposed at the region of the edge 40 of the flap 21 where the covering is bent over such edge in the operation of the brake. The rubber and fabric parts of the inflatable protective covering I6 and theaerodynamic brake ||l -are united .preferably by vulcanization.

In operation, the inflatable tubes I8 of the protective coverings |6, I6 may be connected to a suitable source of supply of pressurized air, for example, and inflated in a cyclic manner for dis- "torting the surfaces of the protective coverings l2 may be connected to a facilitate-ice removal by I6, I6 in order to reduce the adherence of ice formations on the outer surfaces thereof and to the ambient air stream. ||l on the wings and suitable source of pressurized air disposed in the fuselage I4, for example, by hose connectors 4| and 42. When air is admitted to the inflatable tube 31 in a deflated condition, the tube progressively alters its form to assume that form as shown in Fig. 3, and presses against the flap element 21, which action moves the flap element 21 pivotally about the hinge 29 to the braking position thereby presenting an edge at 40 Vto the ambient air stream. The elastic covering 3| during such pivotal movement of the flap element 21 is moved outwardly from the wing l2 and is stretched substantially throughout its extent in a chord-wise direction, hence becoming in a condition of greater tension than when in the retracted position.

As noted hereinabove, when the elastic covering 3| is not adhered to the nap element 21 except at the portion 28 it is stretched throughout its chord-wise extent; whereas, when wholly adhered to the flap element 21, the elastic covering 3| is stretched only in that portion extending from the flap edge at 4B to substantially the margin 33. It is desirable that the elastic covering 3| be not wholly adhered to. the flap 21 in order that some stretching action of the rubber-like material may be induced at its marginal junction with the rubber-like material l1 of the protective covering I6 at the lower margin 2i! for coacting with the rubber-like material l1 in assisting in reducing adhesion of ice accumulation tothe outer surface of the protective covering I6 and the aerodynamic brake IB. During the outward movement of the elastic covering 3| the ller element 38, being adhered thereto moves outwardly likewise and is also stretched in a chord-wise direction.

Upon deflation of the inatable tube 31 the ap element 21 pivots about the hinge 29 under the action of the pressure of the ambient air stream and also the returning action of the stretched elastic covering 3| by virtue of the elasticity of the rubber-like material thereof. Upon completion of the deflation of the tube 31 the aerodynamic brake tends to assume the retracted condition, as shown in Fig. 2, and since the elasticcovering 3| is in a condition of tension the flap element 21 is held in its starting position pressed against the inflatable tube 31 while the filler element 38 resumes its position between the covering 3| and the wing I2 as noted hereinabove. In this manner the aerodynamic brake presents an even outer surface to the flow of air without objectionable bulging and, being in continuation of the protective covering I6, coacts therewith in maintaining the aerodynamic characteristios of the wing l2.

While in the illustrative embodiment the in- The aerodynamic brakes position within the thickness of the covering to an advanced spoiler position, an iniiatable tube normally iiat in the uninated condition and disposed directly beneath said flap element also within the thickness of said covering for moving said flap element from the retracted position to the advanced position upon inflation of said tube, and a sheet element of resilient rubber-like material extending` between said attaching margins and closely overlying said flap element and said tube also within the thickness of said covering and stretchable upon advance of said flap element and contractible to retract said iap element and fiatten said tube upon dei-lation of the latter to restore the thin condition of said covering;

7. A retractible spoiler as definedin claim 6 in which said sheet element has a portion between said rearward attaching margin and said ap element of increased thickness as compared to the thickness of a second portion thereof overlying said flap element to provide a flush surface at the outer face of the covering.

8. A retractible yspoiler as defined in claim' in which said sheet element at a portion 'thereof 8 overlying said fiaprelement is in unattached relation to said flap element at the outer face thereof for relative movement therebetween under the stretching and contraction of the covering.

WILLSON H. HUNTER.

REFERENCES CITED The following references are of record in the le of this patent: 

